Zero-thickness joint/interface elements of the Goodman type, have been advantageously used to solve many problems in solid mechanics involving material interfaces or discontinuities.
These elements are inserted in between standard elements to allow jumps in the solution field, their kinematic constitutive (“strain-type”) variables are relative displacements, and the corresponding static (“stress-type”) variables are stress tractions.
In particular, these elements have been used for representing rock joints in the context of rock masses, contacts between soil and steel reinforcement in reinforced earth structures, or cracks in concrete or other quasi-brittle materials, etc.
Each application may require different constitutive laws, either frictional-type or fracture-based with elasto-plastic structure.
Numerical modeling of Hydraulic Fracture (HF), on the other hand, poses considerable challenge due to the discontinuous nature of fracture, and to the strong coupling between the equations that govern the movement (momentum balance) and the equations that control the fluid pressure (fluid mass continuity). The coupling is due to the mutual influence between fluid and mechanical behavior: on the one side the fluid pressure produces deformations, and on the other side the deformations modify fluid properties (conductivities and storage capacities).
Numerical methods disclosed in the prior art simulate preexisting fracture paths and are not able to predict the fracture opening or fracture branching.
The present invention provides a numerical method allowing the skilled person to simulate a porous medium under complex loading situations such as borehole injection, in which fracture opening and propagation occurs with no need to predefine and impose the geometry of the fracture in the numerical mesh as preexisting fracture, instead the fracture develops spontaneously during the computation, among a set of predefined potential fracture lines.